[英]Passing ifstream as an argument to Class Constructor
I am trying to pass: ifstream infile; 我试图通过:ifstream infile;
in my main (), to the constructor of a class called "FIFO": FIFO (infile); 在我的main()中,创建一个名为“ FIFO”的类的构造函数:FIFO(infile);
In the header file of FIFO (FIFO.h), I have: 在FIFO(FIFO.h)的头文件中,我有:
FIFO (std::ifstream);
std::ifstream infile;
And in FIFO.cc, I have: 在FIFO.cc中,我有:
FIFO::FIFO (std::ifstream & INFILE)
{
infile = INFILE;
}
I kept getting like (There are more of them, I just paste one of them): 我一直在想(有更多它们,我只粘贴其中之一):
In file included from /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/localefwd.h:43, from /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/string:45, from FIFO.cc:7: /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/ios_base.h: In member function 'std::basic_ios >& std::basic_ios >::operator=(const std::basic_ios >&)': /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/ios_base.h:793: error: 'std::ios_base& std::ios_base::operator=(const std::ios_base&)' is private /usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/iosfwd:47: error: within this context 在/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/localefwd.h:43中包含的文件中/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/string:45,来自FIFO.cc:7:/ usr /lib/gcc/x86_64-redhat-linux/4.4.7/../../../../include/c++/4.4.7/bits/ios_base.h:在成员函数'std :: basic_ios> &std :: basic_ios> :: operator =(const std :: basic_ios>&)':/usr/lib/gcc/x86_64-redhat-linux/4.4.7/../../.././ include / c ++ / 4.4.7 / bits / ios_base.h:793:错误:“ std :: ios_base&std :: ios_base :: operator =(const std :: ios_base&)”是私有的/ usr / lib / gcc / x86_64- redhat-linux / 4.4.7 /../../../../ include / c ++ / 4.4.7 / iosfwd:47:错误:在此上下文中
I am not sure if passing ifstream using reference works or not, or it is my codes problem. 我不确定使用引用传递ifstream是否有效,或者这是我的代码问题。
Thanks! 谢谢!
In your constructors declaration you are taking the std::ifstream
by value instead of by reference. 在构造函数声明中,您按值而不是按引用获取
std::ifstream
。 Instead of 代替
FIFO (std::ifstream);
it should be 它应该是
FIFO (std::ifstream&);
and you are storing the member variable 'infile' by value instead of by reference. 并且您通过值而不是通过引用存储成员变量“ infile”。
std::ifstream infile;
should be 应该
std::ifstream& infile;
Since you are now storing a reference to the ifstream you need to initialize it in the initializer list instead of assigning it in the constructor. 由于您现在要存储对ifstream的引用,因此需要在初始值设定项列表中对其进行初始化,而不是在构造函数中进行分配。
FIFO::FIFO (std::ifstream & INFILE)
: infile(INFILE)
{
}
This is because the copy constructor of std::ifstream
is private (or deleted in C++11). 这是因为
std::ifstream
的副本构造函数是私有的(或在C ++ 11中删除)。 By storing the member variable by value you are attempting to make a copy of the std::ifstream
object passed to the constructor. 通过按值存储成员变量,您尝试制作传递给构造函数的
std::ifstream
对象的副本。
The signatures of your prototype declaration and implementation do not match. 原型声明和实现的签名不匹配。 Change
更改
FIFO (std::ifstream);
to 至
FIFO (std::ifstream &);
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